I have a laptop with a broadcom network card. I keep it always powered and have some background processes. I SSH into it and daily the network disconnects at random times. I have to go to the laptop and click on the wifi and connect it manually.

03:00.0 Network controller: Broadcom Inc. and subsidiaries BCM4313 802.11bgn Wireless Network Adapter (rev 01)

My release information is:

Description:    Ubuntu 18.04.3 LTS
Release:        18.04

Any suggestions on what I should look for to solve this?

I am fine with a work around where I reboot through crontab when the network is not available (and hope that fixes it) or restart the network manager.

  • Look at the logs! sudo journalctl -b 0 -u NetworkManager. Read man journalctl.
    – waltinator
    Oct 4 at 3:57
  • If your system is still reporting itself at 18.04.3, you are well behind on security fixes & updates; refer fridge.ubuntu.com/2020/02/12/ubuntu-18-04-4-lts-released and you'll see when 18.04.4 ISO was released; installed systems having updated awhile before that actual ISO release date. A fully upgraded system will report itself as 18.04.6 currently. FYI: You didn't say which kernel stack you're using on your unstated desktop or server install; the other stack choice maybe an easy fix.
    – guiverc
    Oct 4 at 4:43

This is often the result of the power saving feature in Ubuntu. You can disable this for the WiFi device by editing a file and restarting the network manager.

Here's how:

  1. Open Terminal (if it's not already open)

  2. Edit the default-wifi-powersave-on.conf file:

    sudo vi /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf

    Note: Feel free to use any text editor of your choice. Be sure to open it with sudo, though.

    You will see the file contents look like this:

    wifi.powersave = 3
  3. Replace 3 with 2, then save the file.

    Definition of Values:

    Value What It Means
    0 Use the default value
    1 Do not change existing setting(s)
    2 Disable powersave feature
    3 Enable powersave feature
  4. Restart the network manager:

    sudo service network-manager restart

    Alternatively, you could restart the entire system.

This should prevent the device from disconnecting from the network when the system believes it is idle.

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